<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>三种元素类型</title>
    <style>
        .box{
            width: 500px;
            height: 500px;
            border: 2px solid #000;
        }
        .child{
            width: 100px;
            height: 100px;
            background: red;
            display:inline-block;

        }
        .child2{
            width: 50px;
            height: 50px;
            background: green;
            /* 修改元素类型为块级元素 */
            display: block;
        }
    </style>
</head>
<body>
    <div class="box">
        <!-- 文档流，默认从上往下，从左往右 -->
        <div class="child">1234</div>
        <div class="child"></div>

        <span class="child2">123</span>
        <span class="child2">123</span>
    </div>
    
</body>
</html>